Computer data is vital to today's organizations, and a significant part of protection against disasters is focused on data protection. As solid-state memory has advanced to the point where cost of memory has become a relatively insignificant factor, organizations may afford to operate with systems that store and process terabytes of data.
Some data protection systems provide data replication, by creating a copy of an organization's production site data on a secondary backup storage system, and updating the backup with changes. Data replication systems generally operate either at the application level, at the file system level, or at the data block level. Continuous data protection systems can enable an organization to roll back to specific points in time. Some continuous data protection systems use a technology referred to as “journaling,” whereby a log is kept of changes made to the backup storage.
One challenge to continuous data protection is the ability to keep pace with writes (e.g., I/Os or data transactions) occurring at the production site without slowing down the production site. The overhead of journaling may require several writes at the backup site for each write at the production site. As such, when writes occur at a high rate at the production site, the backup site may not be able to finish backing up one write before the next production site write occurs.
U.S. Pat. No. 8,478,955 issued on Jul. 2, 2013 and entitled “VIRTUALIZED CONSISTENCY GROUP USING MORE THAN ONE DATA PROTECTION APPLIANCE,” which is hereby incorporated by reference in its entirety, describes one approach for distributing writes in a continuous replication environment.